from typing import Generator, Optional

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import jwt
from pydantic import ValidationError
from sqlalchemy.orm import Session

from ..core import security
from ..core.config import settings
from ..db.session import SessionLocal
from ..models.user import User
from ..schemas.token import TokenPayload
from ..crud.user import user_crud

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl=f"{settings.API_V1_STR}/auth/login"
)

def get_db() -> Generator:
    try:
        db = SessionLocal()
        yield db
    finally:
        db.close()

def get_current_user(
    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
) -> User:
    try:
        payload = jwt.decode(
            token, settings.JWT_SECRET_KEY, algorithms=[settings.JWT_ALGORITHM]
        )
        token_data = TokenPayload(**payload)
    except (jwt.JWTError, ValidationError):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Could not validate credentials",
        )
    user_obj = user_crud.get(db, id=token_data.sub)
    if not user_obj:
        raise HTTPException(status_code=404, detail="User not found")
    return user_obj

def get_current_active_user(
    current_user: User = Depends(get_current_user),
) -> User:
    if not user_crud.is_active(current_user):
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user

def get_current_active_superuser(
    current_user: User = Depends(get_current_active_user),
) -> User:
    if not user_crud.is_superuser(current_user):
        raise HTTPException(
            status_code=403, detail="The user doesn't have enough privileges"
        )
    return current_user